• 제목/요약/키워드: Aluminum profile

검색결과 102건 처리시간 0.023초

정밀금형 알루미늄 합금주조공정시 주물/금형 접촉면에서의 Inverse 열전달해석에 관한 연구 (Inverse Heat Transfer Analysis at the Mold/Casting Interface in the Aluminum Alloy Casting Process with Precision Metal Mold)

  • 문수동;강신일
    • 한국주조공학회지
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    • 제18권3호
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    • pp.246-253
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    • 1998
  • Precision metal mold casting process is a casting method manufacturing mechanical elements with high precision, having heavy/light alloys as casting materials and using permanent mold. To improve dimensional accuracy and the final mechanical properties of the castings, the solidification speed and the cooling rate of the casting should be controlled with the optimum mold cooling system, and moreover, to obtain more accurate control of the whole process interfacial heat transfer characteristic at the mold/casting interface must be studied in advance. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling system was designed and the temperature histories at points inside the metal mold were measured during the casting process. The heat transfer phenomena at the mold/casting interface was characterized by the heat flux between solidifying casting metal and metal mold, and the heat flux history was obtained using inverse heat conduction method. The effect of mold cooling condition upon the heat flux profile was examined, and the analysis shows that the heat flux value has its maximum at the beginning of the process.

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Advanced Structural Silicone Glazing

  • Kimberlain, Jon;Carbary, Larry;Clift, Charles D.;Hutley, Peter
    • 국제초고층학회논문집
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    • 제2권4호
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    • pp.345-354
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    • 2013
  • This paper presents an advanced engineering technique using finite element analysis to improve structural silicone glazing (SSG) design in high-performance curtain wall systems for building facade. High wind pressures often result in bulky SSG aluminum extrusion profile dimensions. Architectural desire for aesthetically slender curtain wall sight-lines and reduction in aluminum usage led to optimization of structural silicone bite geometry for improved stress distribution through use of finite element analysis of the hyperelastic silicone models. This advanced design technique compared to traditional SSG design highlights differences in stress distribution contours in the silicone sealant. Simplified structural engineering per the traditional SSG design method lacks accurate forecasting of material and stress optimization, as shown in the advanced analysis and design. Full scale physical specimens were tested to verify design capacity in addition to correlate physical test results with the theoretical simulation to provide confidence of the model. This design technique will introduce significant engineering advancement to the curtain wall industry and building facade.

Optical-fiber Electronic Speckle Pattern Interferometry for Quantitative Measurement of Defects on Aluminum Liners in Composite Pressure Vessels

  • Kim, Seong Jong;Kang, Young June;Choi, Nak-Jung
    • Journal of the Optical Society of Korea
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    • 제17권1호
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    • pp.50-56
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    • 2013
  • Optical-fiber electronic speckle pattern interferometry (ESPI) is a non-contact, non-destructive examination technique with the advantages of rapid measurement, high accuracy, and full-field measurement. The optical-fiber ESPI system used in this study was compact and portable with the advantages of easy set-up and signal acquisition. By suitably configuring the optical-fiber ESPI system, producing an image signal in a charge-coupled device camera, and periodically modulating beam phases, we obtained phase information from the speckle pattern using a four-step phase shifting algorithm. Moreover, we compared the actual defect size with that of interference fringes which appeared on a screen after calculating the pixel value according to the distance between the object and the CCD camera. Conventional methods of measuring defects are time-consuming and resource-intensive because the estimated values are relative. However, our simple method could quantitatively estimate the defect length by carrying out numerical analysis for obtaining values on the X-axis in a line profile. The results showed reliable values for average error rates and a decrease in the error rate with increasing defect length or pressure.

2축 시퀀스 제어 스테이지와 미세입자 분사장치에 의한 형상 분사가공시 실험계획법에 의한 주요인자 검출 (Selection of Main Factors by Experimental Analysis for Profile Blast Machining Based on Microparticle Blasting Equipment with a Two-Axis Sequence Control Stage)

  • 황철웅;이세한;왕덕현
    • 한국기계가공학회지
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    • 제19권11호
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    • pp.64-69
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    • 2020
  • To determine the effective factors for microparticle blasting with precise sequence position control in the x-axis and y-axis directions, we conducted a statistical experimental analysis of blasted square shapes by considering five condition factors. The control input and output were operated simultaneously by rotation-linear motion conversion and fine particles were blasted onto the aluminum specimen by precise position control driving using multiple execution codes. The micro-driving device used for processing was capable of microparticle blasting and of controlling the system through contact with a limit sensor at high speed and a two-degree-of-freedom driving mechanism. Our experiments were conducted on 1,050 specimens of pure aluminum (containing <1% of other elements). The effects of several factors (e.g., particle and nozzle diameters, blasting pressure, and federate and blasting cycle numbers) on the surface roughness and blasted surface's depth were verified through a statistical experimental analysis by applying the dispersion analysis method. This statistical analysis revealed that the nozzle diameter, the blasting pressure, and the blasting cycle number were the dominant factors.

표면개량 버블시트 종류 변화가 서중환경 콘크리트의 온도 및 균열발생에 미치는 영향 (Effect of the Kind of Modified Bubble Sheets on the Temperature Profiles and Crack Reduction of the Concrete under Hot Weather)

  • 이상운;한민철
    • 한국건축시공학회지
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    • 제18권3호
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    • pp.251-257
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    • 2018
  • 여름철 콘크리트는 수분증발에 의한 소성 및 건조수축균열, 슬럼프 저하, 콜드조인트 발생 등 다양한 문제가 발생한다. 이에 국내에서는 수분증발을 방지하고, 단열성능을 확보하기 위해 표면피복 양생을 위한 다양한 형태의 버블시트를 제작하여 사용하고 있으나, 여름철에는 적용사례가 없었다. 따라서 본 연구에서는 여름철 시공중인 아파트 현장에 1중의 투명, 백색 및 알루미늄 증착 버블시트와 PE필름 및 표면노출의 5가지 표면피복 양생재를 적용하여 콘크리트의 온도 및 균열특성 등 품질에 미치는 영향을 분석하였다. 실험결과 알루미늄 증착 버블시트가 온도저감, 균열저감 면에서 가장 뛰어난 것으로 나타났지만, 알루미늄 재질의 특성상 빛이 반사되어 시공자의 눈부심에 따른 시각공해가 발생하기 때문에 백색 버블시트의 사용이 가장 효과적인 것으로 밝혀졌다.

Structural design revision of KRISS profilometer for improved measurement accuracy

  • Jung, Kil-Jae;Yang, Ho-Soon;Rhee, Hyug-Gyo;Kim, Yooung-Soo;Lee, Yun-Woo;Kim, Sug-Whan
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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    • pp.31.4-32
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    • 2011
  • The previous KRISS profilometer design used an aluminum profile structure to which a bar-type reference mirror subsystem and the measurement subsystem are mounted. The earlier design suffers from low stiffness as shown from the first resonance mode of 45.1 Hz. The improved mechanical design we describe in this study replaces the aluminium profile structure with a granite structure of $1340{\times}220{\times}230$ in dimension. The finite element analysis results for the revised design show 0.001 degree in probe contact angle variation. The first resonance mode was computed to 91.2 Hz that is much better than 45.1 Hz from the previous design. We describe the improved design, structural analysis results and how these results would satisfy the form accuracy requirement of 1 ${\mu}m$ PV.

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CF4O2 gas 플라즈마를 이용한 폴리이미드 박막의 식각 (The Etching Characteristics of Polyimide Thin Films using CF4O2 Gas Plasma)

  • 강필승;김창일;김상기
    • 한국전기전자재료학회논문지
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    • 제15권5호
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    • pp.393-397
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    • 2002
  • Polyimide (PI) films have been studied widely as the interlayer dielectric materials due to a low dielectric constant, low water absorption, high gap-fill and planarization capability. The polyimide film was etched using inductively coupled plasma system. The etcying characteristics such as etch rate and selectivity were evaluated at different $CF_4/(CF_4+O_2)$chemistry. The maximum etch rate was 8300 ${\AA}/min$ and the selectivity of polyimide to SiO$_2$was 5.9 at $CF_4/(CF_4+O_2)$ of 0.2. Etch profile of polyimide film with an aluminum pattern was measured by a scanning electron microscopy. The vertical profile was approximately $90^{\circ}$ at $CF_4/(CF_4+O_2)$ of 0.2. As 20% $CF_4$ were added into $O_2$ plasma from the results of the optical emission spectroscopy, the radical densities of fluorine and oxygen increased with increasing $CF_4$ concentration in $CF_4/O_2$ from 0 to 20%, resulting in the increased etch rate. The surface reaction of etched PI films was investigated using x-ray photoelectron spectroscopy.

Immunotoxicity Following Pre- and Post-natal Aluminum Exposure in Rats

  • Khalaf, Abd EI-Azeim A.;Morgan, Ashraf M.;Mekawy, Mohey M.;Ali, Maged F.
    • Toxicological Research
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    • 제24권1호
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    • pp.51-58
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    • 2008
  • The present study was designed to explore the immunotoxic effects of orally administered aluminum (AI) on pregnant rats (n = 60) and their growing fetuses and consequently on the animal wealth. The animals were randomly allocated into three equal groups of 20 rats each. The first group has no treatment and kept as a control (G1). The second and third groups of pregnant rats were treated orally with aluminum chloride at 345 mg/Kg b.wt. The second group (G2) received the tested compound from the $6^{th}$ day of gestation to the end of weaning, whereas the third group (G3) received the tested compound from the $15^{th}$h day of gestation to the end of weaning. Control and treated animals (dams and offspring) were immunized ip with (0.5 ml) 20% sheep red blood cell (SRBC) suspension seven days before the end of experiments. At the end of exposure, ten dams and ten offspring from each group were used for assessment of cell-mediated immunity and a similar number of animals were sacrificed for evaluating the humoral immune response and serum protein profile. Aluminum chloride exposure of dams ($G_2&G_3$) caused significant suppression of both cell mediated and humoral immune responses in the obtained offsprings compared to the control group ($G_1$) without any significant effect on the immune responses of these dams. Moreover, the serum total globulins, albumin/ globulin (A/G) ratio and gamma globulin fraction were significantly decreased in the treated dam's offsprings compared to the corresponding controls while the serum total protein and all serum protein fractions showed non significant difference between the control and treated dams and between the two treated dam groups themselves. There were no histopathological changes observed in thymus, spleen and liver of the control and treated dams. Thymus of treated dam's offsprings (G2) showed lymphoid depletion in both cortex and medulla. Their spleens showed lymphoid depletion in the white pulps and congestion with hemosiderosis in the red pulps. Liver of treated dam's offsprings showed dilation and congestion of its central vein with degenerative changes in the hepatocytes. These histopathological changes were more severe in G2 than in G3 offsprings. It can be concluded that gestational and/ or lactation exposure of pregnant dams to AI chloride caused suppression of both cellular and humoral immune responses of their offsprings.

저전압 UHF TV 튜너용 바렉터 다이오드의 제작 및 특성 (Fabrication and Characteristics of a Varactor Diode for UHF TV Tuner Operated within Low Tuning Voltage)

  • 김현식;문영순;손원호;최시영
    • 센서학회지
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    • 제23권3호
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    • pp.185-191
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    • 2014
  • The width of depletion region in a varactor diode can be modulated by varying a reverse bias voltage. Thus, the preferred characteristics of depletion capacitance can obtained by the change in the width of depletion region so that it can select only the desirable frequencies. In this paper, the TV tuner varactor diode fabricated by hyper-abrupt profile control technique is presented. This diode can be operated within 3.3 V of driving voltage with capability of UHF band tuning. To form the hyperabrupt profile, firstly, p+ high concentration shallow junction with $0.2{\mu}m$ of junction depth and $1E+20ions/cm^3$ of surface concentration was formed using $BF_2$ implantation source. Simulation results optimized important factors such as epitaxial thickness and dose quality, diffusion time of n+ layer. To form steep hyper-abrupt profile, Formed n+ profile implanted the $PH_3$ source at Si(100) n-type epitaxial layer that has resistivity of $1.4{\Omega}cm$ and thickness of $2.4{\mu}m$ using p+ high concentration Shallow junction. Aluminum containing to 1% of Si was used as a electrode metal. Area of electrode was $30,200{\mu}m^2$. The C-V and Q-V electric characteristics were investigated by using impedance Analyzer (HP4291B). By controlling of concentration profile by n+ dosage at p+ high concentration shallow junction, the device with maximum $L_F$ at -1.5 V and 21.5~3.47 pF at 0.3~3.3 V was fabricated. We got the appropriate device in driving voltage 3.3 V having hyper-abrupt junction that profile order (m factor) is about -3/2. The deviation of capacitance by hyper-abrupt junction with C0.3 V of initial capacitance is due to the deviation of thermal process, ion implantation and diffusion. The deviation of initial capacitance at 0.3 V can be reduced by control of thermal process tolerance using RTP on wafer.

VVC 다이오드의 시작연구 (I) (Fabrication of Silicon Voltage Variable Capacitance Diode-(I))

  • 정만영;박계영
    • 대한전자공학회논문지
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    • 제5권3호
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    • pp.9-24
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    • 1968
  • 초단계형(Hyperabrupt) p-n접합에서 접합용량의 인가전압에 의한 변화률이 단순물분포에 따라 변화하는 성질을 이용하여 가변용량다이오드의 최적설계방법 유도하고 표준방송수신용 라디오의 동조용 가변용량실리콘 다이오드를 설계하였고 이다이오드의 제작방법에 관하여 연구하였다. 이때 도너 및 액셉터 불순물로서는 안치모니 및 알루미늅을 진공증착한 후 고온확산로에 넣어 처리하므로서 원하는 분포를 얻으려 하였다.

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